Anyone any good with Amazon Fires

[Plump82]

I got one yesterday mainly for reading my kindle however only 4 or 5 of my books are showing? I put the app on my phone have have the same issue. I've synced my kindle and also the app on my phone (can't work out how to do it on the fire) but no joy.
Also my music on Amazon Music is showing.

Go on amazon via Internet and go to kindle and 'Manage content and Devices'. You can then send books to whichever device you want

I have a very old kindle (not kindle fire) but in case it helps - sometimes I find my missing books in an ‘archive’ list that I can download from. It’s one of the menu options.